A Closed Loop System Using a Brine 

Reservoir to Replace Fresh Water as the 

Frac Fluid Source

Minimization of Fresh Water Use: The Use and Reuse of 35000 ppm 

Brine from a Dedicated Deep Reservoir as a Fracture Fluid For Shale

George E. King

Apache Corporation

EPA Workshop on Hydraulic Fracturing

March 29/30, 2011
Acknowledgements

• EnCana – water plant operator and lead 

company on testing of Debolt water.

• Dave Sherman (formerly Apache facilities) –

plant design, water handling solutions, 

emissions reduction, natural gas substitution 

for Diesel fired engines in pad operations. 

Minimizing Fresh Water Usage, George E. 

King, EPA 29/30 March 2011 2
Minimizing Fresh Water Usage, George E. 

King, EPA 29/30 March 2011

3
A Unique Frac Water Source

• Debolt formation, above the Horn River Play 

(British Colombia, Canada)

• Water

– 35,000 ppm TDS

– H2S (10 to 30 ppm?) removed prior to use 

– Temperature of 60C (140F) (useful for cold weather 

operations)

• Minimizes water storage needs

• Minimizes fresh water requirements

• Flow back returned to the Debolt formation.

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King, EPA 29/30 March 2011

Dave Sherman, Apache Canada, 2010

4
Cold Weather Water Pumping

Intrinsic Heat Load for 10” Thin Wall Aluminum Pipe, - 25 C

Water at high rates has enormous specific heat capacity. If water is 

kept moving it can be pumped long distances in cold weather 

without freezing or heat input.

Water specific heat capacity at 16,000 m3/day, 2 Degrees C

What happens when the water stops moving?

Large diameter water piping is a must for cold climate water pumping! Large 

diameter piping makes it possible to address equipment failures prior to piping 

freeze offs.

10" AL Pipe

Time to Freeze

1.0 Length m

50.7 kg water

2.0 Temp Water

-21.2 minutes

6" AL Pipe

Time to Freeze

1.0 Length m

18.2 kg water

2.0 Temp Water

-10.3 minutes

12" AL Pipe

Time to Freeze

1.0 Length m

73.0 kg water

2.0 Temp Water

-27.5 minutes

Daily Water Volume Transferred 16000 m3

Water 

Volume

Tm 5 Deg C

Water 

Temp

Water Vel 3.6 m/s

Water 

Velocity

ID 25.4 m Pipe ID

Tamb -25 Deg C Air Tamb

Air Vel 1.4 m/s

Wind 

Speed

Water Kin Vis 0.000001519 m^2/s

Kin 

Viscosity

k 0.609 W/(m Deg C)

Thermal 

Cond

Pr 11.57 Prandtl Number

Water near 

zero

Reynolds Number UmD/v 601974.9835

Inside Film Coefficient hi =(Nu)*k/Di 4832.525724 W/(m^2*Deg C)

Outside Film Coefficient ho =NU*k/Do 14.02886245 W/(m^2*Deg C)

Overall Heat Transfer Coefficient U =1/(1/hi+1/ho) 13.98825443 W/(m^2*Deg C)

Intrinsic Heat load

Heat Loss Per Meter Pipe Q =A*U*Delta T 334.8639279 W/m

Water Specific Heat Capacity 4.21 kJ/kg*K

Delta T 2 Deg C

Mass Flow 11000 kg/min

1543666.667 =Joule/sec

Meters to Freezing 4609.83 m

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King, EPA 29/30 March 2011 5
Before: Off lease Remote Water Heating 8o C @ 100 bbl/min – > 30 MMBTU/hr

Tight lease space on the d-70-K Pad and LPG fuel storage regulations required an off lease water 

heating solution creating the following special challenges:

Conventional methods were to heat bulk water storage reservoirs typically on lease, not provide instantaneous energy input for 8 C water heat rise 

at 100 BBL / min

Size and type of heat exchanger required for 

water flows at 100 – 125 bbl 

Slipstream and Mix Flows Apache Solution to Enable Compact Portable Heat Exchange of 30,645,580 BTU / Hour

Heat losses in 1,000 m of 12” piping at -25 C

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King, EPA 29/30 March 2011 6
Water Management

• Large volumes of fresh water not required.

• Recycling frac & produced waters

• Higher salinity sources are now usable.

• Chemical Management is Essential

– Biocides under the microscope

• Greener (bio-degradable and no bioaccumulation)

– Lower vol. of chemicals (what’s really needed?)

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King, EPA 29/30 March 2011 7
Brackish Water Source for Fracs

• High perm sand w/ 35,000 ppm, sour (H2S) brine is present ~ 2,000’ above gas 

shale target zone.

• Brine can be supplied at high rate to the treating facility for sweetening and then 

to the frac spread for pumping.

• Flowback water is cleaned and re-injected.

• Advantages:

– Fresh water use is cut to a minimum.

– High Cl- brine eliminates or reduces many chemicals

– Surface storage of frac brine is <<5% of job volume. 

– Higher salinity brine stabilizes shale?

– The hot water from the reservoir eliminates very expensive water heating 

need and eliminates air emissions from the heater

– Cheaper than fresh water for development of multi-well pads

– Lowest Environmental Impact and Smallest Foot Print

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King, EPA 29/30 March 2011 8
•2009 Capital spending to be minimized where possible

•Apache completions to begin October 2009

•Design for average of 3 Fracs a day with enough water for goal of 4 ~ 4,000 m3 fracs per day

•Lowest environmental impact and smallest footprint possible

•Repairs to water system can be performed in a timely fashion using local stock parts

•Follow all of Apache and Encana’s EH&S regulations, ensure safe handling of water

Moderate Salinity Brine Supply for Frac Water

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King, EPA 29/30 March 2011 9
SPE 138222, Pond, et al., (EnCana)

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King, EPA 29/30 March 2011 10
Getting away from fresh water use – Saline Water Supply Schematic

77-K Non Potable 

Water Source Well

Mercaptan 

Scavenger & 

PH Buffer

ACL d-70-K 

Well Pad

Fresh Water 

Make - Up

67-K Plant Inlet 

Separator

Fresh Water Lake

C-67-K/94-O-08 Etsho 

Compressor Station & 

Water Plant Site

Borrow Pits For 

Freshwater Storage 

Only

67-K Non Potable 

Water Source Well

ACL d-52-L 

Well Pad

Produced Shale Gas & Fracture Stimulation Flowback Water

Treated Non Potable Source Water for 

Fracture Stimulations

Separator 

Vessels & 

Treated Water 

Storage Tanks

90-J Non Potable Water 

Disposal Well

Debolt Reservoir (ASR) 

Non-Potable Aquifer 

Storage Reservoir

Produced Natural 

Gas to Spectra Sales 

Tie-In

Produced 

Fracture 

Stimulation 

Flowback 

Water

* Closed system, no storage of treated water in un-lined burrow pits. 

* Water Recycle Line, 

Stimulation Flowback 

Water Compatibility 

Under Review

Minimal 

Use

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King, EPA 29/30 March 2011 11
Debolt Water Analysis

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King, EPA 29/30 March 2011 12
Flow Back vs. Time

3 bbls/minute

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Flowback water from a shale frac.

The yellow color is from iron in 

contact with oxygen from the air.

Slight adjustment to pH results in a 

clear solution. 

Background salinity varies with the 

shale.
Minimizing Fresh Water Usage, George E. 

King, EPA 29/30 March 2011 15

Ion variation in the backflow

Matt Blauch, SPE
Conclusions

• Debolt source water is from a regional sour aquifer with a TDS level 

unsuitable for either agriculture or drinking water. 

• Use of Debolt water required a series of tests focused on water 

treatment, formation interaction and disposal potential.

• Environmental impact improvements are seen in a number of areas:

– Closed loop system – no oxygen and minimal flare/venting.

– Minimize water heater emissions using hot Debolt water (~140F/60C) 

to prevent freezing in the -20C operations.

– Minimize fresh water usage - still used in surface drill & cementing. 

– Possible reduction of biocides & elimination of some other chemicals.

– Reduce surface frac water storage to <<5% of total needed

– Reduction of surface pipe & draw from lakes.

– Reduction of truck traffic and roads by using the closed-loop system.

• Pad design (16 wells on 6.3 acres drains >2500 acres). Sharp 

reduction in roads, pipelines, facilities and traffic.

• Possible shale stability improvements with more saline water.

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King, EPA 29/30 March 2011 16
Support Slides

• Forward Osmosis Clean-Up

• Water Districts and Plastic Pipe Supply Lines

• Types of Treatment

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King, EPA 29/30 March 2011 17
Cleaning Up Drilling Fluids

Water treated by 

forward osmosis is 

not fresh water – it 

is a clean saline base 

fluid that can be 

used for fracturing.

Salinity of the water 

delivered by FO can 

be programmed. 

18 Minimizing Fresh Water Usage, George E. 

King, EPA 29/30 March 2011
Water Districts

• Flexible (e.g., HDPE) pipes – surface or 

subsurface to transfer water to and from wells 

without truck traffic. 

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